Continuous variable valve duration apparatus and engine provided with the same

ABSTRACT

A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a slider housing in which the first and the second inner brackets are rotatably inserted; first and second guiding portions formed on the slider housing; a control shaft parallel to the camshaft; a control rod eccentrically formed on the control shaft; a guide head on which a head guiding portion and a head hole are formed; a cam cap supporting the control shaft; a cam cap guiding portion mounted to the cam cap; and a control portion selectively rotating the control shaft such that the slider housing is moved along the cam cap guiding portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2015-0178650, filed on Dec. 14, 2015, the entirecontents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a continuous variable valve durationapparatus and an engine provided with the same.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

An internal combustion engine generates power by burning fuel in acombustion chamber in an air media drawn into the chamber. Intake valvesare operated by a camshaft in order to intake the air, and the air isdrawn into the combustion chamber while the intake valves are open. Inaddition, exhaust valves are operated by the camshaft, and a combustiongas is exhausted from the combustion chamber while the exhaust valvesare open.

Optimal operation of the intake valves and the exhaust valves depends ona rotation speed of the engine. That is, an optimal lift or optimalopening/closing timing of the valves depends on the rotation speed ofthe engine. In order to achieve such optimal valve operation dependingon the rotation speed of the engine, various researches, such asdesigning of a plurality of cams and a continuous variable valve lift(CVVL) that can change valve lift according to engine speed, have beenundertaken.

Also, in order to achieve such an optimal valve operation depending onthe rotation speed of the engine, research has been undertaken on acontinuously variable valve timing (CVVT) apparatus that enablesdifferent valve timing operations depending on the engine speed. Thegeneral CVVT may change valve timing with a fixed valve openingduration.

However, the general CVVL and CVVT are complicated in construction andare expensive in manufacturing cost.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the present disclosureand therefore it may contain information that does not form the priorart that is already known to a person of ordinary skill in the art.

SUMMARY

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

Various aspects of the present disclosure provide a continuous variablevalve duration apparatus and an engine provided with the same which mayvary opening duration of a valve according to operation conditions of anengine, with a simple construction.

A continuous variable valve duration apparatus according to an exemplaryform of the present disclosure may include: a camshaft; first and secondcam portions on which a cam is formed respectively, the camshaft beinginserted into the first and second cam portions such that relative phaseangles with respect to the camshaft are variable; first and second innerbrackets transmitting rotation of the camshaft to the first and secondcam portions respectively; a slider housing in which the first and thesecond inner brackets are rotatably inserted, wherein a first guidingportion is formed on an upper portion of the slider housing, and asecond guiding portion vertical to the first guiding portion is formedon the slider housing; a control shaft parallel to the camshaft and acontrol rod eccentrically formed on the control shaft; a guide head onwhich a head guiding portion and a head hole are formed, wherein thehead guiding portion is slidably connected to the first guiding portion,and the control rod is rotatable insert into the head hole; a cam capsupporting the control shaft; a cam cap guiding portion mounted to thecam cap and guiding movement of the slider housing; and a controlportion selectively rotating the control shaft such that the sliderhousing is moved along the cam cap guiding portion.

The first guiding portion and the head guiding portion may be slidablyengaged with a rail shape.

A guide rail may be formed on the cam cap guiding portion and is engagedwith the second guiding portion.

A shaft hole in which the control shaft is inserted may be formed in thecam cap.

The continuous variable valve duration apparatus may further include ashaft bearing inserted into the shaft hole and rotatably supporting thecontrol shaft.

The cam may be formed on the first and the second cam portions as apair, a cam cap connecting portion may be formed between the two cams ofeach cam portion, and a cam support for rotatably supporting the camconnecting portion may be formed on the cam cap.

A cam key may be formed on the first and second cam portionsrespectively, first and second sliding holes may be formed in the firstand second inner brackets respectively, a cam key pin may be rotatablyinserted into the each first sliding hole, wherein a cam key slot isformed in the cam key pin and the cam key is slidably inserted into thecam key slot, a camshaft pin may be connected to the camshaft, and aslider pin may be rotatably inserted into the each second sliding hole,wherein a camshaft pin slot is formed in the slider pin, and thecamshaft pin is slidably inserted into the camshaft pin slot.

The continuous variable valve duration apparatus may further include aslider housing bearing disposed between the slider housing and the firstand the second inner brackets respectively.

The continuous variable valve duration apparatus may further include aspacer disposed within the slider housing for inhibiting or preventingrotations of the first and the second inner brackets from beinginterrupted.

The control portion may include a worm wheel connected with the controlshaft, a worm gear engaged with the worm wheel and a control motorselectively rotating the worm gear.

A cam key may be is formed on the first and second cam portionsrespectively, first and second sliding holes may be formed in the firstand second inner brackets respectively, a cam key pin may be rotatablyinserted into the each first sliding hole, wherein a cam key slot isformed in the cam key pin, and the cam key is slidably inserted into thecam key slot, and a slider pin may include a pin body and a pin headintegrally formed with the pin body. In particular, the pin body may beslidably inserted into the camshaft and the pin head may be rotatablyinserted into the second sliding hole.

A camshaft oil hole may be formed to the camshaft along a lengthdirection thereof, a body oil hole communicated with the camshaft oilhole may be formed to the pin body, and an oil groove communicated withthe body oil hole may be formed to the pin head.

An engine according to an exemplary form of the present disclosure mayinclude: a camshaft; first and second cam portions on which a cam isformed respectively, the camshaft being inserted into the first andsecond cam portions such that relative phase angles with respect to thecamshaft are variable; first and second inner brackets transmittingrotation of the camshaft to the first and second cam portionsrespectively; a slider housing in which the first and the second innerbrackets are rotatably inserted, wherein a first guiding portion isformed on an upper portion of the slider housing, and a second guidingportion vertical to the first guiding portion is formed on the sliderhousing; a control shaft parallel to the camshaft, and a control rod iseccentrically formed on the control shaft; a guide head on which a headguiding portion and a head hole are formed, wherein the head guidingportion is slidably connected to the first guiding portion, and thecontrol rod is rotatable insert into the head hole; a cam cap supportingthe control shaft; a cam cap guiding portion mounted to the cam cap andguiding movement of the slider housing; and a control portionselectively rotating the control shaft such that the slider housing ismoved along the cam cap guiding portion.

The first guiding portion and the head guiding portion may be slidablyengaged with a rail shape.

A guide rail may be formed on the cam cap guiding portion and is engagedwith the second guiding portion.

A shaft hole in which the control shaft is inserted may be formed in thecam cap.

The engine may further include a shaft bearing inserted into the shafthole and rotatably supporting the control shaft.

The cam may be formed on the first and the second cam portions as apair, a cam cap connecting portion may be formed between the two cams ofeach of the first and second cam portions, and a cam support forrotatably supporting the cam connecting portion may be formed on the camcap.

The engine may further include: a cam key formed on the first and secondcam portions respectively; first and second sliding holes formed in thefirst and second inner brackets respectively; a cam key pin rotatablyinserted into the each first sliding hole, wherein a cam key slot isformed in the cam key pin, and the cam key is slidably inserted into thecam key slot; a camshaft pin connected to the camshaft; and a slider pinrotatably inserted into the each second sliding hole, wherein a camshaftpin slot is formed in the slider pin, and the camshaft pin is slidablyinserted into the camshaft pin slot. In another form, a cam key may beis formed on the first and second cam portions respectively, first andsecond sliding holes may be formed in the first and second innerbrackets respectively, a cam key pin may be rotatably inserted into theeach first sliding hole, a cam key slot may be formed in the cam keypin, the cam key is slidably inserted into the cam key slot, and aslider pin may include a pin body and a pin head integrally formed withthe pin body. In particular, the pin body may be slidably inserted intothe camshaft and the pin head may be rotatably inserted into the secondsliding hole.

In still another form, a camshaft oil hole may be formed in the camshaftalong a length direction of the camshaft, a body oil hole communicatedwith the camshaft oil hole may be formed in the pin body, and an oilgroove communicated with the body oil hole may be formed in the pinhead.

As described above, the continuous variable valve duration apparatusaccording to an exemplary form of the present disclosure may vary anopening duration of a valve according to operation conditions of anengine, with a simple construction.

The exemplary continuous variable valve duration apparatus of thepresent disclosure may be reduced in size and thus the entire height ofa valve train may be reduced.

Since the continuous variable valve duration apparatus may be applied toan existing engine without excessive modification, thus productivity maybe enhance and production cost may be reduced.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a perspective view of an engine provided with a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure;

FIG. 2 is a perspective view of a continuous variable valve durationapparatus according to an exemplary form of the present disclosure;

FIG. 3 is an exploded perspective view showing a guide head and a sliderhousing of the continuous variable valve duration apparatus according toan exemplary form of the present disclosure;

FIGS. 4A-4C are cross-sectional views showing operations of an exemplarycontinuous variable valve duration apparatus of the present disclosure;

FIGS. 5 and 6 are exploded perspective views of the exemplary continuousvariable valve duration apparatus of the present disclosure;

FIG. 7 is a cross-sectional view along line VII-VII of FIG. 1;

FIG. 8 is a table showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure;

FIG. 9 is a graph showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure; and

FIG. 10 is a drawing showing a slider pin of a continuous variable valveduration apparatus according to a modified form of the presentdisclosure.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

As those skilled in the art would realize, the described forms may bemodified in various different ways, all without departing from thespirit or scope of the present disclosure.

A part irrelevant to the description will be omitted to clearly describethe present disclosure.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity.

Throughout the specification and the claims, unless explicitly describedto the contrary, the word “comprise” and variations such as “comprises”or “comprising”, will be understood to imply the inclusion of statedelements but not the exclusion of any other elements.

FIG. 1 is a perspective view of an engine provided with a continuousvariable valve duration apparatus, and FIG. 2 is a perspective view of acontinuous variable valve duration apparatus.

FIG. 3 is an exploded perspective view showing a guide head and a sliderhousing of the continuous variable valve duration apparatus, and FIGS.4A-4C are cross-sectional views showing operations of an exemplarycontinuous variable valve duration apparatus.

FIGS. 5 and 6 are exploded perspective views of the exemplary continuousvariable valve duration apparatus, and FIG. 7 is a cross-sectional viewalong line VII-VII of FIG. 1.

Referring to FIG. 1 to FIG. 7, an engine 1 includes a cylinder head 10,and a continuous variable valve duration apparatus mounted to thecylinder head 10. The cylinder head may include a cam carrier.

The continuous variable valve duration apparatus includes: a camshaft30; first and second cam portions 70 a and 70 b on which camS 71 and 72are formed respectively, the camshaft 30 being inserted into the firstand second cam portions such that relative phase angles with respect tothe camshaft 30 are variable; first and second inner brackets 80 and 81transmitting rotation of the camshaft 30 to the first and second camportions 70 a and 70 b respectively; a slider housing 90 in which thefirst and the second inner brackets 80 and 81 are rotatably inserted afirst guiding portion 93 formed on an upper portion of the sliderhousing; a second guiding portion 95 which is vertical to the firstguiding portion 93 and formed on the slider housing; a control shaft 108which is parallel to the camshaft 30 and on which a control rod 110 iseccentrically formed; a guide head 50 on which a head guiding portion 52slidably connected to the first guiding portion 93 is formed; a headhole 54 formed on the guide head, and the control rod 110 beingrotatable inserted into the head hole; a cam cap 40 supporting thecontrol shaft 108; a cam cap guiding portion 62 mounted to the cam cap40 and guiding movement of the slider housing 90; and a control portion100 selectively rotating the control shaft 108 such that the sliderhousing 90 is moved along the cam cap guiding portion 62.

The camshaft 30 may be an intake camshaft or an exhaust camshaft and isrotated by a cam sprocket 48 connected with a crankshaft.

In the present disclosure, 4 cylinders 211, 212, 213 and 214 are formedto the engine, but it is not limited thereto.

The first guiding portion 93 and the head guiding portion 52 areslidably engaged with a rail shape. In the drawings, although the firstguiding portion 93 is formed as a “T” shape and the head guiding portion52 is shaped as covering the first guiding portion 93, it is not limitedthereto. On the contrary, the head guiding portion 52 may be shaped as a“T” shape and the first guiding portion 93 may be formed as covering thefirst guiding portion 93, or other engaged shapes such as rails may bepossible.

A guide rail 64 engaged with the second guiding portion 95 is formed onthe cam cap guiding portion 62.

In one form, a cam cap guiding portion engage hole 66 may be formed inthe cam cap guiding portion 62, a cam cap engage hole 47 may be formedin the cam cap 40, and an engage bolt 65 may be inserted into the camcap guiding portion engage hole 66 and the cam cap engage hole 47. Sincethe cam cap guide 62 which is separately formed is engaged with the camcap 40, thus vibration or noise due to accumulated tolerance of elementsmay be alleviated or suppressed.

The second guiding portion 95 and the guide rail 64 are slidably engagedwith a rail shape.

The first guiding portion 93 and the head guiding portion 52 areslidable to each other, the second guiding portion 95 and the guide rail64 are slidable to each other, and eccentric rotation of the control rod110 is transferred to left and right direction movement of the guidehead 50 and up and down direction movement of the slider housing 90.Thus, smooth and precise control of a position of the slider housing 90may be possible.

The cam cap 40 may be formed integrally or as shown in the drawing maybe assembly by a cam cap upper body 40 a and a cam cap lower body 40 b.

A shaft bearing 44 is mounted to the shaft hole 42 and rotatablysupports the control shaft 108.

Two cams 71 and 72 may be formed to the first and the second cam portion70 a and 70 b respectively and a cam connecting portion 76 may be formedbetween the two cams 71 and 72. And a cam supporting portion 44 isformed on the cam cap 40 for rotatably supporting the cam connectingportion 76.

The cams 71 and 72 rotate and open the valve 200.

A cam key 74 is formed on the first and second cam portions 70 a and 70b respectively, and a first sliding hole 86 and a second sliding hole 88are formed in the first and second inner brackets 80 and 81respectively.

A cam key pin 82 is rotatably inserted into the each first sliding hole86, and a cam key slot 83 may formed on the cam key pin 82. The cam key74 is slidably inserted to the cam key slot 83.

A camshaft hole 32 is formed in the camshaft 30 and a camshaft pin 60 isinserted into the camshaft hole 32 to be connected to the camshaft 30.And a slider pin 84 is rotatably inserted into the each second slidinghole 88, and a camshaft pin slot 85 is formed in the slider pin 84. Thecamshaft pin 60 is slidably inserted into the camshaft pin slot 85.

A slider housing bearing 92 may be disposed between slider housing 90and the first and the second inner brackets 80 and 81 respectively, andthus relative rotations between the each slider housing 90 and the firstand the second inner brackets 80 and 81 and rigidity may be obtained.The slider housing bearing 92 may be a needle bearing, a ball bearing, aroller bearing and so on, but it is not limited thereto.

A spacer 91 is disposed in the slider housing 90 and between the firstand second inner brackets 80 and 81 for inhibiting or preventing therotations of the first and second inner brackets 80 and 81 from beinginterrupted.

As shown in FIG. 7, since the slider housing 90 is disposed between thefirst cam portion 70 a and the second cam portion 70 b, engine layoutmay be simplified and one slider housing 90 may control rotational speedof the first cam portion 70 a and the second cam portion 70 bsimultaneously. Thus, the continuous variable valve duration apparatusmay be constructed with simplified and elements number may be reduced.

Also, since elements for controlling the valve duration may be reduced,thus power loss of the engine may be reduced.

The control portion 100 includes a worm wheel 102 connected with thecontrol shaft 108, a worm gear 104 engaged with the worm wheel 102 and acontrol motor 106 selectively rotating the worm gear 104. By applyingthe worm wheel 102 and the worm gear 104, thus motor capacity of thecontrol motor 106 may be reduced.

FIG. 8 is a table showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure and FIG. 9is a graph showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure.

Referring to FIG. 1 to FIG. 9, operations of the exemplary continuousvariable valve duration apparatus will be described.

When rotation centers of the camshaft 30 and the first and second innerbrackets 80 and 81 are coincident, that is, the slider housing 90 ispositioned at an original position as shown in FIG. 8, the cams 71 and72 rotate with the same phase angle of the camshaft 30. That is, thecams 71 and 72 and the camshaft 30 rotate with the same speed.

According to engine operation states, an ECU (engine control unit orelectric control unit) transmits control signals to the control motor106 of the control portion 100 to rotate the control shaft 108. Then,the control rod 110 eccentrically formed to the control shaft 108rotates and the rotation of the control rod 110 is transferred to leftand right direction movement of the guide head 50 and up and downdirection movement of the slider housing 90.

According to the rotation of the control shaft 108, positions of theslider housing 90 and the first and the second inner brackets 80 and 81with respect to a rotation center of the camshaft 30 are changed upwardor downward.

When, the position of the slider housing 90 with respect to the camshaft30 is changed, the relative rotation speed of the cams 71 and 72 withrespect to the rotation speed of the camshaft 30 are changed.

While the camshaft pin 60 is rotated together with the camshaft 30, thecamshaft pin 60 is slidable within the camshaft pin slot 85, the sliderpin 84 is rotatably inserted into the second sliding hole 88, the camkey pin 82 is rotatably inserted into the first sliding hole 86, and thecam key 74 is slidable within the cam key slot 83. Thus the relativerotation speed of the cams 71 and 72 with respect to the rotation speedof the camshaft 30 is changed.

As shown in FIGS. 4A-4C, while the phase angle of the camshaft 30 isconstantly changed when the relative position of the slider housing 90with respect to the rotation center of the camshaft 30 is changeddownward as ΔH1, as shown in FIG. 8, the rotation speed of the cams 71and 72 is relatively slower than rotation speed of the camshaft 30 near60 to 120 degree, then then the rotation speed of the cams 71 and 72 isrelatively faster than rotation speed of the camshaft 30 near 240 to 300degree.

As shown in FIGS. 4A-4C, while the phase angle of the camshaft 30 isconstantly changed when the relative position of the slider housing 90with respect to the rotation center of the camshaft 30 is changed upwardas ΔH2, as shown in FIG. 8, the rotation speed of the cams 71 and 72 isrelatively faster than rotation speed of the camshaft 30 near 60 to 120degree, then then the rotation speed of the cams 71 and 72 is relativelyslower than rotation speed of the camshaft 30 near 240 to 300 degree.

That is, as shown in FIG. 9 valve duration D2 in the case that therelative position of the slider housing 90 is changed to ΔH1 is shorterthan valve duration D1 in the case that the position of the sliderhousing 90 is at the original position.

Also, valve duration D3 in the case that the relative position of theslider housing 90 is changed to ΔH2 is longer than valve duration D1 inthe case that the position of the slider housing 90 is at the originalposition.

In FIG. 9, for better comprehension and ease of description, peak pointsin FIG. 10 are constant, but it is not limited thereto.

According to adjusting contacting positions of the valve 200 and the cam71 and 72, contacting angles of the valve 200 and the cam 71 and 72, aposition of the cam key 74 and so on, valve duration may be enlarged byadvancing opening timing and retarding closing timing of the valve 200.Or, valve duration may be shortened by retarding opening timing andadvancing closing timing of the valve 200.

Also, opening timing of the valve 200 may be constant and closing timingof the valve 200 may be retarded or advanced as requested.

Also, closing timing of the valve 200 may be constant and opening timingof the valve 200 may be retarded or advanced as requested.

FIG. 10 is a drawing showing a slider pin of a continuous variable valveduration apparatus according to a modified form of the presentdisclosure.

In the exemplary form, the camshaft pin 60 and the slider pin 84 may bedisconnected, and a slider pin 84 (160 as shown in FIG. 10) may includea pin body 162 slidably inserted into the camshaft hole 32 of camshaft30 and a pin head 164 which is integrally formed with the pin body 162and rotatably inserted into the second sliding hole 88.

A camshaft oil hole 34 (referring to FIG. 7) is formed in the camshaft30 along a length direction thereof and a body oil hole 166 communicatedwith the camshaft oil hole 34 is formed in the pin body 162.

And an oil groove 168 communicated with the body oil hole 166 through acommunicating hole 169 is formed in the pin head 164.

Since lubricant may be supplied from the camshaft oil hole 34 to the oilgroove 168 through the body oil hole 166 and the communicating hole 169,thus friction between the pin head 164 and the second sliding hole 88may be reduced.

Except the slider pin, operations and structures of the continuousvariable valve duration apparatus according to a modified form of thepresent disclosure are the same of the exemplary form described above,repeated description will be omitted.

As described above, the exemplary continuous variable valve durationapparatus of the present disclosure may perform various valve durationsaccording to operation conditions of an engine.

The exemplary continuous variable valve duration apparatus of thepresent disclosure may be reduced in size and thus the entire height ofa valve train may be reduced.

Particularly, since the motor and so on of the control portion may bemounted outside of the cam carrier thus the entire height of an enginemay be reduced.

While this present disclosure has been described in connection with whatis presently considered to be practical exemplary forms, it is to beunderstood that the present disclosure is not limited to the disclosedforms. On the contrary, it is intended to cover various modificationsand equivalent arrangements included within the spirit and scope of thepresent disclosure.

<Description of Symbols>

1: engine 10: cylinder head 30: camshaft 32: camshaft hole 40: cam cap42: shaft hole 44: shaft bearing 46: cam supporting portion 47: cam capengage hole 48: cam sprocket 50: guide head 52: head guiding portion 54:head hole 60: camshaft pin 62: cam cap guiding portion 64: guide rail65: engage bolt 66: cam cap guiding portion engage hole 70a, 70b: first,second cam portion 71, 72: cam 74: cam key 76: cam connecting portion80: first inner bracket 81: second inner bracket 82: cam key pin 83: camkey slot 84: slider pin 85: camshaft pin slot 86: first sliding hole 88:second sliding hole 90: slider housing 91: spacer 92: slider housingbearing 93: first guiding portion 95: second guiding portion 100:control portion 102: worm wheel 104: worm gear 106: control motor 108:control shaft 110: control rod 160: slider pin 162: pin body 164: pinhead 166: body oil hole 168: oil groove 169: communicate hole 200: valve211-214: 1-4 cylinder

What is claimed is:
 1. A continuous variable valve duration apparatuscomprising: a camshaft; first and second cam portions on which a cam isformed respectively, the camshaft being inserted into the first andsecond cam portion such that relative phase angles with respect to thecamshaft are variable; first and second inner brackets configured totransmit rotation of the camshaft to the first and second cam portionsrespectively; a slider housing in which the first and the second innerbrackets are rotatably inserted, wherein a first guiding portion isformed on an upper portion of the slider housing, and a second guidingportion vertical to the first guiding portion is formed on the sliderhousing; a control shaft parallel to the camshaft, and a control rodeccentrically formed on the control shaft; a guide head on which a headguiding portion and a head hole are formed, wherein the head guidingportion is slidably connected to the first guiding portion, and thecontrol rod is rotatable insert into the head hole; a cam cap configuredto support the control shaft; a cam cap guiding portion mounted to thecam cap and guiding movement of the slider housing; and a controlportion configured to selectively rotate the control shaft such that theslider housing is moved along the cam cap guiding portion.
 2. Thecontinuous variable valve duration apparatus of claim 1, wherein thefirst guiding portion and the head guiding portion are slidably engagedwith a rail shape.
 3. The continuous variable valve duration apparatusof claim 1, wherein a guide rail is formed on the cam cap guidingportion and is engaged with the second guiding portion.
 4. Thecontinuous variable valve duration apparatus of claim 1, wherein a shafthole in which the control shaft is inserted is formed in the cam cap. 5.The continuous variable valve duration apparatus of claim 4, furthercomprising a shaft bearing inserted into the shaft hole and rotatablysupporting the control shaft.
 6. The continuous variable valve durationapparatus of claim 1, wherein the cam is formed on the first and thesecond cam portions as a pair, and a cam cap connecting portion isformed between the paired cams of each of the first and second camportions, and a cam support configured to rotatably support the camconnecting portion is formed on the cam cap.
 7. The continuous variablevalve duration apparatus of claim 1, further comprising: a cam keyformed on the first and second cam portions, respectively; first andsecond sliding holes formed in the first and second inner brackets,respectively; a cam key pin rotatably inserted into the each firstsliding hole, wherein a cam key slot is formed in the cam key pin, andthe cam key is slidably inserted into the cam key slot; a camshaft pinconnected to the camshaft; and a slider pin rotatably inserted into theeach second sliding hole, wherein a camshaft pin slot is formed in theslider pin, and the camshaft pin is slidably inserted into the camshaftpin slot.
 8. The continuous variable valve duration apparatus of claim1, further comprising a slider housing bearing disposed between theslider housing and the first and the second inner brackets respectively.9. The continuous variable valve duration apparatus of claim 8, furthercomprising a spacer disposed within the slider housing so as to inhibitrotations of the first and the second inner brackets from beinginterrupted.
 10. The continuous variable valve duration apparatus ofclaim 1, wherein the control portion comprises: a worm wheel connectedwith the control shaft; a worm gear engaged with the worm wheel; and acontrol motor selectively rotating the worm gear.
 11. The continuousvariable valve duration apparatus of claim 1, further comprising: a camkey formed on the first and second cam portions, respectively; first andsecond sliding holes formed in the first and second inner brackets,respectively; a cam key pin rotatably inserted into the each firstsliding hole, wherein a cam key slot is formed in the cam key pin, andthe cam key is slidably inserted into the cam key slot; and a slider pinincluding a pin body and a pin head integrally formed with the pin body,and wherein the pin body is slidably inserted into the camshaft, and thepin head is rotatably inserted into the second sliding hole.
 12. Thecontinuous variable valve duration apparatus of claim 11, furthercomprising: a camshaft oil hole formed in the camshaft along a lengthdirection thereof; a body oil hole formed in the pin body and configuredto communicate with the camshaft oil hole; and an oil groove formed inthe pin head and configured to communicate with the body oil hole. 13.An engine comprising: a camshaft; first and second cam portions on whicha cam is formed respectively, the camshaft being inserted to the firstand second cam portions such that relative phase angles with respect tothe camshaft are variable; first and second inner brackets configured totransmit rotation of the camshaft to the first and second cam portionsrespectively; a slider housing in which the first and the second innerbrackets are rotatably inserted, wherein a first guiding portion isformed on an upper portion of the slider housing, and a second guidingportion vertical to the first guiding portion is formed on the sliderhousing; a control shaft parallel to the camshaft, and a control rodeccentrically formed on the control shaft; a guide head on which a headguiding portion and a head hole are formed, wherein the head guidingportion is slidably connected to the first guiding portion, and thecontrol rod is rotatable insert into the head hole; a cam cap configuredto support the control shaft; a cam cap guiding portion mounted to thecam cap and guiding movement of the slider housing; and a controlportion configured to selectively rotate the control shaft such that theslider housing is moved along the cam cap guiding portion.
 14. Theengine of claim 13, wherein the first guiding portion and the headguiding portion are slidably engaged with a rail shape.
 15. The engineof claim 13, wherein a guide rail is formed on the cam cap guidingportion and is engaged with the second guiding portion.
 16. The engineof claim 13, wherein a shaft hole in which the control shaft is insertedis formed in the cam cap.
 17. The engine of claim 16, further comprisinga shaft bearing inserted into the shaft hole and rotatably supportingthe control shaft.
 18. The engine of claim 13, wherein the cam is formedon the first and the second cam portions as a pair, and a cam capconnecting portion is formed between the paired cams of each of thefirst and second cam portions, and a cam support for rotatablysupporting the cam connecting portion is formed on the cam cap.
 19. Theengine of claim 13, further comprising: a cam key formed on the firstand second cam portions, respectively; first and second sliding holesformed in the first and second inner brackets, respectively; a cam keypin rotatably inserted into the each first sliding hole, wherein a camkey slot is formed in the cam key pin, and the cam key is slidablyinserted into the cam key slot; a camshaft pin connected to thecamshaft; and a slider pin rotatably inserted into the each secondsliding hole, wherein a camshaft pin slot is formed in the slider pin,and the camshaft pin is slidably inserted into the camshaft pin slot.20. The engine of claim 13, further comprising: a cam key formed on thefirst and second cam portions, respectively; first and second slidingholes formed in the first and second inner brackets, respectively; a camkey pin rotatably inserted into the each first sliding hole, wherein acam key slot is formed in the cam key pin, and the cam key is slidablyinserted into the cam key slot; and a slider pin including a pin bodyand a pin head integrally formed with the pin body, and wherein the pinbody is slidably inserted into the camshaft and the pin head isrotatably inserted into the second sliding hole.
 21. The engine of claim20, further comprising: a camshaft oil hole formed in the camshaft alonga length direction thereof; a body oil hole formed in the pin body andconfigured to communicate with the camshaft oil hole; and an oil grooveformed in the pin head and configured to communicate with the body oilhole.